In Canadian Pat. No. 994,215 issued Aug. 3, 1976 to Baldrey et al, there is described a strain mechanism for loading the saw of a bandmill. The strain mechanism comprises a yoke assembly which is slidably mounted within a column forming part of bandmill and which includes a hinge portion. A carrier arm supports the arbor of one of the wheels of the bandmill and is equipped with a hinge portion which is complementary to the hinge portion of the yoke assembly so as to form a hinge to journal the carrier arm to the yoke assembly to permit rotation of the arm relative to the yoke assembly. An air spring extends between the carrier arm and the yoke assembly to rotate the carrier arm relative to the yoke assembly to strain the saw.
The central axis of the arbor carrying the wheel is at some distance from the hinge axis of the yoke assembly and the carrier arm. It has been found that the distance separating these two axes is such as to allow a twisting effect to occur in cases where the strain exerted on one mechanism located on one side of the wheel is different from that on the other mechanism on the other side of the wheel. This may occur, for example, when uneven pneumatic pressure exists in the air springs or when there are variations in strain crosswise of the saw resulting from either variation in its construction or from uneven wear.